🧹IODD TRIM Tool
IODD TRIM Tool is a universal TRIM utility that improves SSD write speeds for any external USB drive.
Version: 0.2.0.4 Platform: Windows 64-bit License: Freeware
1. Overview
The IODD TRIM Tool is a Windows-exclusive application designed to send TRIM commands to external SSDs connected via a USB-SATA bridge.
Universal Compatibility This tool is not limited to IODD products—it supports all external USB SSDs from any manufacturer, as long as the USB bridge supports ATA Pass-Through or SCSI UNMAP.
While Windows automatically performs TRIM on internal SATA/NVMe SSDs, this automatic function does not work for external SSDs connected through a USB bridge. This tool is designed to maintain the performance and extend the lifespan of such external SSDs.
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Key Features
3-Step TRIM Strategy: Automatic fallback from DSM TRIM → SCSI UNMAP → ATA Pass-Through.
BOT/UASP Support: BOT prioritizes ATA Pass-Through, while UASP prioritizes SCSI UNMAP.
Full Device TRIM: Sends TRIM commands to the entire SSD area.
Free Space Only TRIM: Performs TRIM only on empty space, preserving existing files.
Real Test: Verifies if TRIM is actually working by performing a file write/delete/verify sequence.
Write Speed Chart: Records speeds at 2-second intervals during the Real Test and displays them on a time-series chart.
Drive Inspection: Provides detailed information on disk partitions, volumes, and free space.
Dry Run Mode: Simulates the process without sending actual TRIM commands.
Read-only Drive Detection: Automatically disables file output when run on a read-only drive.
8 Languages Supported: Korean, English, Japanese, Simplified Chinese, Spanish, German, French, and Russian.
🚀 Quick Start Guide
Select your device from the dropdown menu at the top.
Choose a TRIM Mode:
Full Device TRIM: Completely wipes the SSD. ALL data will be permanently deleted. Use this only when initializing a new or repurposed drive.
Free Space Only TRIM: Only trims the unused empty space. Your existing files remain safe. Use this to optimize performance on a drive you are currently using.
Click the Start button to execute TRIM.
2. System Requirements
OS
Windows 10 / 11 (64-bit)
Privileges
Administrator privileges required (needed for SCSI Pass-Through)
Connection
SSD connected via a USB-SATA bridge
Protocol
Supports both BOT (Bulk-Only Transport) and UASP (USB Attached SCSI Protocol)
Important: You must run the application with Administrator privileges. Standard user permissions cannot send SCSI Pass-Through commands to the disk.
3. What is TRIM?
TRIM is an ATA command (DATA SET MANAGEMENT, 0x06) that tells the SSD which data blocks are no longer in use.
Benefits of TRIM
Maintains Write Performance: Pre-emptively secures empty blocks to prevent write speed degradation.
Extends SSD Lifespan: Reduces unnecessary write/erase cycles, minimizing NAND wear.
Consistent Response Times: Maintains stable performance even after long periods of use.
Efficient Space Management: Optimizes the SSD controller's internal garbage collection.
When should you use TRIM?
After deleting a large number of files.
When the SSD's write speed has noticeably slowed down.
After using a USB external SSD for a long time without TRIM.
When the OS does not support automatic TRIM for USB-connected SSDs.
4. UI Layout
The app consists of a top toolbar and 3 main tabs.
5. Top Toolbar
IODD Products
Opens the IODD product page (Amazon) in your browser.
IODD Manual
Opens the IODD help site (help.iodd.kr) in your browser.
Usage
Displays a usage guide popup.
License
Displays a popup with freeware license information.
TRIM Info
Displays a popup explaining the benefits and timing of TRIM.
Language Selection
Changes the app's UI language (dropdown on the top right).
6. Execute TRIM Tab
This is the main tab where you send TRIM commands to the selected disk.
6.1 Disk Selection
Select the target disk from the dropdown menu at the top. Each item displays the following information:
PD Number: Physical Drive number
Model Name: SSD model
Capacity: Total disk capacity (GiB)
Protocol: BOT (ATA Pass-Through) / UAS (SCSI UNMAP) / Non-USB
Volume: Drive letter + File system
TRIM Support: TRIM:YES / TRIM:NO / APT:N/A
You can rescan the disk list using the Refresh button.
6.2 Disk Info Memo
When a disk is selected, detailed information appears in the memo box below:
Model, Serial, Capacity, Transfer Protocol
Volume info (File system, Cluster size, Offset, Partition length in GiB)
ATA Pass-Through support status
TRIM Capable status
ATA Model, Firmware info
6.3 TRIM Mode
Full Device TRIM
Sends TRIM to the entire disk. ALL data will be permanently deleted.
Free Space Only
Trims only the empty space on the file system. Existing files are preserved.
Warning: Full Device TRIM permanently deletes all data on the disk. Be sure to back up your data before using this mode.
6.4 TRIM Transmission Methods
Depending on the disk's protocol, a 3-step automatic fallback strategy is applied:
1
DSM TRIM
Windows Native TRIM (Attempted while the volume is mounted)
2
SCSI UNMAP
For UASP devices. Attempted after Volume Lock/Dismount if DSM TRIM fails
3
ATA Pass-Through
Default for BOT devices. Final fallback if SCSI UNMAP fails
BOT Devices: Directly sends via ATA Pass-Through.
UASP Devices: Attempts DSM TRIM → SCSI UNMAP → ATA Pass-Through in order.
SCSI UNMAP attempts multi-descriptor mode first, then switches to single-descriptor mode if rejected.
6.5 Options
Dry Run
Simulates the operation without sending actual TRIM commands.
OFF
Flush Volumes
Flushes the volume buffers before performing TRIM.
ON
Init after TRIM
Initializes the disk to GPT/MBR after TRIM is complete.
None
6.6 Advanced Settings
Checking the Show Advanced Settings box reveals additional options:
Timeout (ms)
SCSI timeout duration for each TRIM batch.
5,000ms
Retry
Number of retries upon failure.
3
Batch Entries
Number of TRIM ranges to send at once.
32
Batch Limit
Maximum number of batches (1, 10, 100, All).
All
Allow System Disk
Allows TRIM on the OS system disk.
OFF
Mask Serial
Masks the serial number in logs.
ON
6.7 Execution
Select the disk.
Select the TRIM mode.
Click the Start button.
Verify by entering the disk number in the warning confirmation dialog.
The progress will be shown on the progress bar and status bar.
A success/failure popup will appear upon completion.
You can immediately stop an ongoing TRIM by clicking the Cancel button.
6.8 USB Notice
You can view guidance regarding the USB bridge device's protocol:
BOT: Sends TRIM via ATA Pass-Through.
UASP: Sends TRIM via SCSI UNMAP (falls back to ATA Pass-Through if failed).
If TRIM fails:
Unplug and reconnect the device directly.
Try changing the USB hub or cable.
Refresh and check the Transport protocol.
7. Drive Inspect Tab
Investigates detailed partition and volume information of the selected disk.
Features
Run Inspection: Retrieves detailed volume information for the selected disk.
Export Free Space CSV: Outputs the free space ranges as a CSV file.
Displayed Information — Summary
Disk model, size (GiB + total sectors), number of volumes, list of file systems
Total space, free space, used space (bytes / clusters / sectors / ratio)
Additional info: Transport protocol, BusHint
Number of free fragments, Free sectors, Free GiB, Last used LBA
Displayed Information — Volume Grid
Drive
Drive letter
FS
File system (NTFS, FAT32, exFAT, etc.)
Partition#
Partition number
Style
Partition style (GPT / MBR)
Type
Partition type
Sec/Cluster
Sectors per cluster
Total Sectors
Total number of sectors
Size (GB)
Capacity (GB)
Free Sectors
Free sectors count (Ratio %)
Used Sectors
Used sectors count (Ratio %)
Physical Start Sector
Physical starting sector
Partition Length Sectors
Partition length (sectors)
Cluster Bytes
Cluster size (bytes)
8. Real Test Tab
Verifies whether TRIM is actually functioning on the SSD through a file write/delete/verify process.
Note: It is not mandatory to run the Real Test for standard TRIM usage. This feature is intended to verify if the USB bridge controller and this software properly execute TRIM on your specific SSD. If verification is needed, running it once is sufficient. The time required depends on the disk capacity and USB speed, taking approximately 6 hours for a 1TB SSD.
8.1 Test Procedure (STEP 1~4)
STEP 1
TRIM + Fill Files
First executes Free-space TRIM, then fills 1/3 of the remaining capacity with 500MB random files.
STEP 2
Delete + TRIM
Deletes 1 in every 10 files → Flushes → Extracts Free Space CSV → Performs Free-space TRIM.
STEP 3
Additional Fill
Fills the remaining capacity with 1GB random files (leaving about 1GB of free space).
STEP 4
Integrity Verify
Verifies the CRC integrity of the 500MB files.
In STEP 1, TRIM is executed before creating files to ensure the SSD starts the test in an optimal write performance state.
8.2 Options
Start Step
The step number to start from (1~4).
End Step
The step number to end at (1~4).
Target Drive
Select the logical drive to use for the Real Test.
Wait on Drop
Wait time (minutes) if write speed drops below 50% of the moving average. Set to 0 to disable.
8.3 Sudden Speed Drop Detection
If the SSD cache is exhausted during writing, the speed may drop sharply. This feature:
Tracks the average speed based on an EMA (Exponential Moving Average).
If the 2-second interval speed drops to 50% or less of the moving average, it pauses for the set duration.
Speed is recorded as 0 while waiting, and automatically resumes afterward.
8.4 Buttons
Start
Begins the entire test (STEP 1~4). A confirmation popup appears before starting.
Verify Only
Only verifies the CRC integrity of existing files (corresponds to STEP 4).
Stop
Immediately halts the ongoing test.
Delete Test Folder
Deletes the temporary files/folders used for the test.
Export FileMap
Exports the physical location map of the test files as a CSV.
Speed Chart
Displays the time-series write speed chart of the last test (enabled after completion).
Clear Log
Clears the log and redisplays the instructional message.
8.5 Write Speed Chart
Clicking the Speed Chart button after a test is completed displays a time-series line chart:
X-axis: Elapsed time, Y-axis: Write speed (MB/s).
Speed data measured at 2-second intervals is shown as a blue line.
Dotted lines mark the boundaries of each STEP, allowing you to see performance changes per stage at a glance.
Waiting periods are recorded as 0 speed.
You can save the data as a CSV file using the Save CSV button.
8.6 Status Display
Status: The currently executing step.
Speed: Real-time write speed (2-second interval average, MB/s).
Elapsed: Total elapsed time (updates every second).
Step: Elapsed time for the current step (updates every second).
8.7 TRIM Result Log
After each TRIM execution, the results are output to the log:
8.8 Test Completion
Upon completion, a success/failure popup appears:
Success: If all file CRCs match, it means TRIM is functioning correctly.
Failure: If a CRC mismatch occurs, there may be data corruption after TRIM.
Cancelled: If the user pressed the Stop button.
9. Multilingual Support
You can change the language from the dropdown in the top right corner of the app. The OS language is automatically detected and set as the default.
Korean
한국어
English
English
Japanese
日本語
Simplified Chinese
简体中文
Spanish
Español
German
Deutsch
French
Français
Russian
Русский
10. Frequently Asked Questions (FAQ)
Q: TRIM fails on a UASP device.
On UASP devices, the tool automatically tries DSM TRIM → SCSI UNMAP → ATA Pass-Through in order. If all fail:
Try unplugging the device and reconnecting it directly.
Try changing the USB hub or cable.
Some USB bridges simply do not support TRIM commands.
Q: It says ATA Pass-Through is not supported.
This happens when the USB bridge controller does not support ATA Pass-Through. However, if connected via UASP, TRIM is transmitted via SCSI UNMAP, so TRIM might still be possible even without ATA Pass-Through.
Q: It displays TRIM:NO.
This means ATA Pass-Through is supported, but the SSD itself does not support TRIM. This happens with very old SSDs or traditional HDDs. TRIM is a command exclusively for SSDs.
Q: Free Space Only TRIM fails with a "No free-space bitmap ranges available" error.
This occurs when the file system bitmap cannot be read. Ensure that you are using a supported file system (NTFS, FAT32, exFAT).
Q: The disk is not recognized after a Full Device TRIM.
After a full TRIM, the partition table may be deleted. If you set the Init after TRIM option to GPT or MBR, it will automatically initialize the disk afterward.
Q: I am getting an error even though I ran it with Administrator privileges.
Some antivirus software may block SCSI Pass-Through commands. Try temporarily disabling your antivirus and run it again.
Q: [WARN] DSM TRIM winerr=1 appears in the log.
This is normal behavior. The USB bridge does not support Windows DSM TRIM, so it automatically fell back to SCSI UNMAP. As long as the final TRIM is successful, there is no issue.
Q: [WARN] SCSI UNMAP winerr=1117 appears in the log.
This is normal behavior. The bridge rejected multiple descriptors, so it automatically switched to single-descriptor mode. As long as the final TRIM is successful, there is no issue.
Q: The Speed Chart button is disabled.
Speed data is only collected after running the Real Test at least once. The button becomes enabled after a test is completed.
11. Troubleshooting
Disk does not appear in list
Bad USB cable or not connected
Check USB connection and refresh
"Admin Privileges Required" error
Ran with standard user rights
Right-click app → "Run as Administrator"
APT:N/A displayed
USB bridge lacks ATA command support
Handled automatically via SCSI UNMAP if UASP
TRIM batch failed
Timeout or bridge compatibility issue
Increase timeout value, decrease batch size
DSM TRIM winerr=5
Attempted while volume is dismounted
Automatic fallback will handle it (Normal)
SCSI UNMAP winerr=5
Attempted while volume is mounted
Retries automatically after Lock/Dismount (Normal)
CRC mismatch in Real Test
Data area corrupted after TRIM
Possible bridge/SSD compatibility issue
Wait on Drop doesn't trigger
Wait time is set to 0
Set the wait on drop value to 1 or higher
CSV/Log files are not created
Ran on a read-only drive
Run from a writable drive
12. License
The IODD TRIM Tool is Freeware.
Anyone can use it for free, and it may be freely copied and distributed.
This software is provided "AS IS".
Commercial sales are strictly prohibited.
The developer assumes no responsibility for any damages, including data loss, resulting from the use of this software.
Reverse engineering, decompiling, and source code extraction are prohibited.
Copyright (c) 2025-2026 IODD. All rights reserved.
This manual is based on IODD TRIM Tool v0.2.0.4.
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